Question: Simplify the following expression: $r = \dfrac{2x + 9}{6x - 3} - \dfrac{9x - 3}{6x - 3}$
Solution: Since the expressions have the same denominator we simply subtract the numerators: $r = \dfrac{2x + 9 - (9x - 3)}{6x - 3}$ Distribute the negative sign: $r = \dfrac{2x + 9 - 9x + 3}{6x - 3}$ Combine like terms: $r = \dfrac{-7x + 12}{6x - 3}$